Want to smooth and brighten, fade dark spots, and boost collagen production? Topical skin care products containing vitamin C often claim to do all of this and more. In fact, vitamin C has completely blown up within the past two years, with countless brands releasing their own serums and creams featuring the "it" ingredient. The downside: They can be really damn expensive, which has prevented me from buying them in the past.

So I ordered up a bottle to see if it would "transform" my own dull, flaky, relatively lackluster skin that's been acquiring its fair share of fine lines lately—but not without first consulting some dermatologists on what I could realistically expect.

Turns out, vitamin C really does hold promise for skin health. Our skin has a higher concentration of vitamin C than other tissues in the body, and lower skin levels of vitamin C are associated with sun damage and signs of aging. "Topical vitamin C is a natural antioxidant that can help prevent free radical damage from environmental elements such as pollutants and UV light, which can lead to premature aging," says Lisa Airan, M.D., a dermatologist specializing in high-tech, natural skin care.

Using vitamin C topically has also been shown to increase collagen production and hydration and reduce discoloration in the skin. According to holistic dermatologist Cybele Fishman, M.D., vitamin C directly stimulates collagen synthesis and may help even out skin tone because it "inhibits tyrosinase, which is the key enzyme in pigment production, through its interaction with copper."

But not all topical vitamin C products are created equal, and not all forms of vitamin C have been equally studied. "A lot of the vitamin C products out there are not very good because vitamin C is unstable, especially when it's exposed to the sun," said Dr. Fishman. Holistic dermatologist Alan Dattner, M.D., agrees, stating that poorly formulated products may actually act as pro-oxidants. Ideally, a product will be packaged in a dark or opaque bottle, and if the serum is brown, it has likely already oxidized, rendering it useless.

Additionally, while there are many different types of vitamin C derivatives being used in skin care products, L-ascorbic acid is the only active form of vitamin C and the only form shown to effectively penetrate the skin. Most experts recommend seeking out a product with this ingredient, ideally present with plenty of additional antioxidant ingredients to keep it stable and help prevent oxidation, says Dattner. Other vitamin C derivatives, such as SAP (used in the TruSkin Naturals product), may be effective, but the research just isn't there to confirm whether they penetrate deeply enough to yield meaningful results.

So, with the pros and cons in mind, I decided to go forth and apply TruSkin Naturals Vitamin C Serum twice a day, after cleansing and before using my favorite face oil. When I received the product, it was packaged in a dark amber bottle and had no visible signs of oxidation. After my first couple of applications, I experienced no irritation but also no major improvements (some Amazon reviewers spoke of instantaneous results). However, after about a week, nearly all of the rough dry patches on my face were gone, and while it didn't completely prevent new breakouts, my blemishes seemed to heal and fade faster than usual, contributing to an overall more even skin tone. As for fine lines, they were still there but maybe a little less noticeable? It was hard to tell, but I could certainly see the appeal.

While the TruSkin Naturals' ingredient list is packed with mostly natural ingredients, Dattner did point out that the serum contains phenoxyethanol, an antimicrobial preservative that can be irritating for some. While it's deemed safe for adults in concentrations of 1 percent or lower, it's still something to be mindful of, especially if you experience a rash or redness when you spot test with this product. "The best [vitamin C] option would be preservative-free," he says.

Overall, I was pretty pleased with the results of this serum, and I'm sold on vitamin C for skin health. Even though results weren't instantaneous, the skin-smoothing effect was still pretty quick, and I'm curious to see what other changes I notice going forward.